It appears that Alessandro Vesely  <ves...@tana.it> said:
>Hi,
>
>    The domain in the RFC5322.From header field is extracted as the
>    domain to be evaluated by DMARC.  If the domain is encoded with UTF-
>    8, the domain name must be converted to an A-label, as described in
>    Section 2.3 of [RFC5890], for further processing.
>
>Why?  That paragraph is almost identical to its 7489 version.  However, since 
>then, RFC 8616 established that d= in DKIM signatures is a U-label.  In that 
>case, to check alignment, the domain name must be converted to U-label.  Of 
>course, to perform a DNS lookup names must be converted to A-label.  To use 
>the 
>PSL, for those who do, names must be converted to U-label.  In one sentence, a 
>verifier must be prepared to convert domain names as needed.
>
>I'd just strike that paragraph.

If you have EAI mail, which you do if you have a UTF-8 domain in a From header, 
the U-label form is preferred.

It'd be better to say that in an EAI environment, A-labels and U-labels are 
equivalent,
and per RFC 8616 you should use the U-label in A-R headers.  Don't have a 
strong opinion
about what goes into the reports but in aggregate reports, A-labels would 
likely surprise
fewer people.

R's,
John

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